How It Sees

Goodbye to all that
This is the final cleaned-up image. How did we banish the blizzard? First, we
flagged sharp features appearing in one image but not the other as cosmic-ray
garbage and discarded them. Then we combined the two "snow"-free images to
improve the signal-to-noise ratio. We also corrected for a number of
instrumental effects with names like "dark current," "flat fields," and "charge
transfer inefficiencies." No need to bore you with details of those effects,
even though as a member of the team that built the camera I spent a couple of
years figuring out how to characterize and remove them!

Despite all these efforts, some cosmic rays and other defects remain that we
need to jettison.